The use of diamond as an optical component such as a flat window, prism, or lens in an optical tool is known. For example, JP 9028715, JP 5095962, U.S. Pat. No. 4,170,997 and U.S. Pat. No. 6,104,853 disclose the use of diamond as a window material disposed in the end of a medical laser tool. Diamond is useful as a window material as it has low absorption. Diamond has the additional advantage over other possible window materials in that it is mechanically strong, inert, and biocompatible. For example, the inertness of diamond makes it an excellent choice for use in reactive chemical environments where other optical window materials would not be suitable.
One problem with using diamond as a window material is that the diamond window has a tendency to de-bond from the optical tool to which it is attached, for example due to chemical and/or thermal conditions. Another related problem when faced with designing an optical tool for use in reactive chemical environments is how to improve diamond window bonding whilst also ensuring that the optical tool is chemically inert to the reactive chemical environments in which it is to be used.
It is an aim of certain embodiments of the present invention to solve the aforementioned problems. In particular, certain embodiments of the present invention seek to provide an optical tool which is stable, reliable, has improved lifetime, and can be made small in size. Particular embodiments are aimed at providing a chemically inert optical probe with a diamond window, particularly for insertion into harsh chemical environments to perform spectroscopic analysis such as in a chemical reactor housing acidic reactants. Application areas include the pharmaceuticals industry where manufacturers are required to provide process data including a chemical analysis of their processes.